Automatic part-circle sprinklers are known in the art. Many are designed to attach to underground water pipes and incorporate pop-up heads which rise above the ground when water is supplied to the sprinkler and which lie flush with the ground when not in use.
The limitations of the part-circle sprinklers found in the prior art are numerous. First, most utilize complicated control mechanisms which are susceptible to being jammed by the various debris flowing through the water pipes of most sprinkler systems. As a result, expensive screens are required to protect the control mechanisms.
Second, in many of the part-circle sprinklers found in the prior art, the limits of coverage of the sprinkler are set internally within the sprinkler and thus partial disassembly of the sprinkler is usually required when these limits are to be changed.
Third, in those sprinklers which provide a precise adjustment of the area of coverage, the sprinkler rotates only to the preset limit of rotation. As a result, the presence of any wind or a slight misadjustment of the area of coverage often results in the outer limits of the area not being sprayed with water.
Finally, most of the devices found in the prior art have no means for maintaining a constant speed of rotation when sudden changes occur in the volume of water supplied to the device. As a result, these volume changes cause erratic operation of these part-circle sprinklers.
Accordingly, it is a principal object of this invention to reduce the complexity of the control mechanism required in a part-circle sprinkler.
It is another object of this invention to simplify the adjustment of the limits of rotation of a part-circle sprinkler.
It is still another object of this invention to insure that the outer limits of the predetermined area of coverage of a part-circle sprinkler receive adequate water.
It is a final object of this invention to prevent volumetric changes in the water supplied to a part-circle sprinkler from disturbing its speed of rotation.